Q. 303.9( 41 Votes )
(i) A lens produc
(i) When a convex or converging lens forms a real image, the magnification is considered negative. This is so because the image is inverted.
When the beam of light passes through the optic center, the ray shouldn’t deviate. Here when the girl was playing with the laser beam with convex lens placed vertically, the ray must be passing through the optical center.
The reason being that the middle part of a lens is like a thin glass slab, so almost no deviation takes place and very slight lateral displacement of the incident ray takes place.
We know from Snell’s law; refractive index of a medium is given by-
n = refractive index
c=speed of light in vacuum
v=speed of light in medium
In medium, speed of light becomes 1/2
So refractive index becomes,
Refractive index of slab = n1
Refractive index of medium = n2
(i)When n1> n2, the incident ray bends away from the normal of glass slab as shown in fig. below
(ii) When n1 = n2, there won’t be any refraction
(iii)When n1< n2, the ray of light will bend towards the normal as shown in fig. below.
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(a) State snell’sScience - Board Papers